The present invention relates generally to an ankle-foot orthosis and, more particularly, to an easily removable ankle-foot orthosis adapted for limiting range of motion of the ankle joint, subtalar joint and midtarsal joints of the foot while maintaining a relative approximately 90.degree. relationship between the foot and leg.
The ankle joint, that joint formed by the articulation of the inferior surfaces of the tibia and fibula with the superior, medial and lateral surfaces of the talus, and the subtalar joint, that joint formed between the inferior surface of the talus and superior surface of the calcaneus bones of the foot are primarily effected by limited ranges of motion. The ranges of motion that occur are in the cardinal body planes, transverse, frontal and sagital, and are in varying degrees. The forces which initiate motion, which are muscle function and other biomechanical influences, are altered by the orthosis to accomplish the limited range of motion.
It is necessary at various times to limit ankle joint and subtalar joint motion as described above. For example, it is normally necessary to limit movement of the ankle joint and subtalar joint to promote healing thereof after surgery or bone fusion, after minor injuries such as bone fractures and ligament strains and to compensate for certain neuro muscular or musculo-skeletal disorders such as dropfoot and for inflammatory disease of tendons, tendon separations and other soft tissue disorders. Also, limitation of the ankle joint and subtalar joint if frequently prescribed for treating certain arthritic conditions. A device for limiting movement of the ankle joint and subtalar joint is referred to as an ankle-foot orthosis, the device having as its primary function that of maintaining the foot and leg in a substantially 90.degree. relationship to one another.
Prior art ankle foot orthosis have taken a number of different forms. Conventionally, plaster casts, metal bracings and other synthetic products as fiber casts, have been used to immobilize the ankle joint to promote healing. In addition, since the devices are not readily removable, the wearer cannot bath nor ambulate conveniently. More recently, vacuum forming and extrusion molding techniques have been used to custom make polypropylene total contact orthosis. The present invention is lighter in weight and easier to apply than plaster casts and metal bracings. The orthosis facilitates immediate ambulation after application. The device allows quick removal and re-application in order to facilitate clinical evaluation and physical therapy. This invention will utilize for the most part there fabricating techniques to produce this foot and ankle orthosis.